On 5/25/21 12:23 PM, Yejune Deng wrote: > Use DEFINE_RAW_SPINLOCK instead of DEFINE_SPINLOCK object_map_lock > that won't be preempted on mainline and PREEMPT_RT kernels. > > Signed-off-by: Yejune Deng <yejunedeng@xxxxxxxxx> RT tree also has such patch, with IMHO more thorough description: https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/tree/patches/0002-mm-slub-Make-object_map_lock-a-raw_spinlock_t.patch?h=linux-5.12.y-rt-patches I was planning to include that in the next version of my series as that will indeed be necessary. > --- > mm/slub.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/mm/slub.c b/mm/slub.c > index c2f63c3..995f3d0 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -445,7 +445,7 @@ static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page, > > #ifdef CONFIG_SLUB_DEBUG > static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)]; > -static DEFINE_SPINLOCK(object_map_lock); > +static DEFINE_RAW_SPINLOCK(object_map_lock); > > #if IS_ENABLED(CONFIG_KUNIT) > static bool slab_add_kunit_errors(void) > @@ -481,7 +481,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page) > > VM_BUG_ON(!irqs_disabled()); > > - spin_lock(&object_map_lock); > + raw_spin_lock(&object_map_lock); > > bitmap_zero(object_map, page->objects); > > @@ -494,7 +494,7 @@ static unsigned long *get_map(struct kmem_cache *s, struct page *page) > static void put_map(unsigned long *map) __releases(&object_map_lock) > { > VM_BUG_ON(map != object_map); > - spin_unlock(&object_map_lock); > + raw_spin_unlock(&object_map_lock); > } > > static inline unsigned int size_from_object(struct kmem_cache *s) >
